Should We Avoid Oils for Optimal Health? Here’s Where Top WFPB Experts Stand on the Great Oil Debate

Is olive oil a wholesome kitchen staple, a dietary landmine, or something in between? The answer depends on who you ask. Since the debut of the Forks Over Knives film in 2011, FOK has followed and shared the advice of whole-food, plant-based (WFPB) pioneers who’ve long counseled heart disease patients to steer clear of all added oils—even olive oil—because they are the world’s most calorie-dense foods, highly refined and stripped of most nutrients other than fat.

Based on groundbreaking research of Caldwell B. Esselstyn Jr., M.D., at the Cleveland Clinic, and T. Colin Campbell, Ph.D., at Cornell, the low-fat WFPB lifestyle began as a therapeutic diet to help people with heart disease turn their health around. Low-fat plant-based diets have also been shown to reverse Type 2 diabetes and help with obesity and other chronic conditions. For people who aren’t facing major health challenges, it’s a way to stop lifestyle-driven diseases before they start.

The guiding principle of the WFPB diet is a focus on whole (or minimally processed) plant-based foods, which are dense with nutrients and fiber yet low in saturated fat and calories. It’s a nutritional one-two punch that nourishes the body while helping people lose the excess weight that often leads to chronic disease. When you go the next step and replace added oil with whole-food sources of fat (think avocados, nuts, and seeds), you can further drive up nutrients and drive down calories, effectively supercharging the diet.

But not all experts in the WFPB space agree that going oil-free is a necessary step for reaping benefits of a WFPB lifestyle, and we believe our audience deserves to hear what they have to say. Enter The Great Oil Debate, our bid to shine a light on how leading plant-based physicians and nutritionists currently think about added oils in the diet.

To kick things off, we hosted a live debate featuring two leading voices in the plant-based world: Garth Davis, M.D., board-certified bariatric surgeon, obesity medicine specialist, and author of Proteinaholic: How Our Obsession With Meat Is Killing Us and What We Can Do About It, and Rip Esselstyn, founder of PLANTSTRONG Foods; author of several books, including The Engine 2 Diet series; and son of WFPB pioneer Caldwell B. Esselstyn, M.D.

In the lead-up to the live debate, Forks Over Knives reached out to several leading WFPB physicians and nutritionists to ask the big question: How do you counsel your patients/audience on consuming olive oil and vegetable oils? Some of them also opted to answer a bonus question: Do you personally avoid all added oils, even in small amounts? Why or why not? Read on for their answers.

A pioneer of the whole-food, plant-based movement, Dr. Esselstyn was featured prominently in the Forks Over Knives film. He is the director of Esselstyn Heart Disease Program at The Cleveland Clinic and author of the New York Times best-seller Prevent and Reverse Heart Disease: The Revolutionary, Scientifically Proven, Nutrition-Based Cure.

How do you counsel patients on consuming olive oil and vegetable oils?

Dr. Esselstyn: “The patients I counsel are almost uniformly sick with heart disease. And heart disease really has its onset when we progressively injure the delicate innermost lining of the artery, the endothelium. Why is that important? Because the endothelium is responsible for making this magic molecule of gas called nitric oxide.

“What are the functions of nitric oxide? Number one, it keeps all the cellular elements within our bloodstream flowing smoothly. It keeps things from getting sticky. Number two, it’s the strongest blood vessel dilator in the body. When you climb stairs, your arteries to your heart and legs, they expand, they dilate. That's nitric oxide. Number three, nitric oxide protects the arterial walls from becoming thick and stiff or inflamed and protects us from getting hypertension. Number four is key: A normal amount of nitric oxide protects us from developing blockages and plaques. Literally everybody on Earth who has cardiovascular disease has it because over the previous decades they’ve sufficiently injured and compromised their endothelial system.

“The good news is that this is not a malignancy; it’s a foodborne illness. What are the foods that injure the endothelium? It’s any drop of oil: olive oil, corn oil, soybean oil, safflower oil, sunflower oil, coconut oil, palm oil. Oil on a cracker, oil on a chip, oil on a piece of bread, oil in a salad dressing. Once patients understand that never again are they to pass through their lips a single morsel that would further injure a damaged endothelium, then the endothelium will recover and make enough nitric oxide to halt disease progression. And we often see significant disease reversal.”

Do you personally avoid added oils?

Dr. Esselstyn: “We don't eat any oil, whether it's at home or out or at restaurants.”

Another expert prominently featured in the Forks Over Knives film, Dr. Campbell co-authored the groundbreaking book The China Study: Startling Implications for Diet, Weight Loss and Long Term Health. He is the Jacob Gould Schurman Professor Emeritus of Nutritional Biochemistry at Cornell University and founder of the nonprofit T. Colin Campbell Center for Nutrition Studies.

Dr. Campbell did not respond to our request for comment, but his position on added oils is clearly stated on the Center for Nutrition Studies website: “Even the finest olive oils are 100% fat, meaning calorically dense and nutrient-poor. Oil injures the endothelium, the innermost lining of the artery, and that injury is the gateway to vascular disease. Especially for those with known heart disease, adding even a little oil can negatively impact heart health.”

The president of the Physicians Committee for Responsible Medicine, Dr. Barnard is a New York Times bestselling author of 20-plus books and more than 100 scientific publications.

How do you counsel patients on consuming olive oil and vegetable oils?

Dr. Barnard: “Plant oils are generally much healthier than animal fats, because they are lower in saturated (‘bad’) fat, which is linked to high cholesterol levels and Alzheimer’s disease. The exceptions are coconut and palm oil, which are loaded with saturated fat—not unlike animal fats.

“But even ‘healthier’ oils and fats have the same high calorie content, and they all contribute to insulin resistance and hormonal problems, so minimizing them is a good idea. Here’s our approach: We help patients to learn oil-free methods in food preparation: Use a nonstick pan, sauté in water or vegetable broth, choose nonfat salad toppings, and read labels so you can buy lower-fat products. Soon, people come to prefer the lighter tastes.”

Dr. Ornish is president and founder of the nonprofit Preventive Medicine Research Institute in Sausalito, California, and clinical professor of medicine at the University of California, San Francisco. He is the author of seven bestselling books, including Dr. Dean Ornish’s Program for Reversing Heart Disease. His Ornish Lifestyle Medicine program is a nine-week, Medicare-covered program for reversing heart disease using a very low-fat (10% of total calories) plant-based diet.

How do you counsel patients on consuming olive oil and vegetable oils?

Dr. Ornish: “My lifestyle medicine program is based on science, which evolves over time as we learn more. It’s remarkable how little my recommendations have changed since I developed and studied this lifestyle medicine program for reversing heart disease almost 50 years ago.

“In 1981, for example, I began recommending that people add three grams per day of algae-based omega-3 fatty acids to their diet based on new research at the time documenting their many health benefits which were initially documented by my mentor, Dr. Alexander Leaf, who was Chief of Medicine at Harvard Medical School at the time. I remember talking at the time with a group of dietitians who said, ‘You can’t add oil to the Ornish diet!’

“In that spirit, I used to preclude seeds and nuts because they are high in oils and fat. Several years ago, I became impressed with a variety of studies showing that regular consumption of nuts and seeds is associated with a reduced risk of heart disease and other chronic conditions. Consuming approximately 15 grams of nuts and seeds daily can decrease the risk of coronary heart disease by around 20%. This is about 3–4 small handfuls a week of unsalted nuts and seeds that are not roasted in oil. Especially beneficial are walnuts, almonds, flaxseeds, pistachios, and cashews.

“While these benefits may come from nutrients such as omega-3 fatty acids, vitamin E, and magnesium, there is a germinative quality of seeds and nuts—life ready to burst forth—that we may have a hard time measuring but may play an important role. Seeds and nuts provide a broader spectrum of nutrients than added oils, which are highly processed, dense in calories, and often inflammatory.”

A board-certified bariatric surgeon and obesity medicine specialist in Houston, Texas, Dr. Davis serves as medical director of Houston Methodist Comprehensive Weight Management Center. He is the author of Proteinaholic: How Our Obsession With Meat Is Killing Us and What We Can Do About It.

How do you counsel patients on consuming olive oil and vegetable oils?

Dr. Davis: “I discuss the fact that oils are not intrinsically bad, but they are calorie dense. I recommend being conscious of the fact that they are calorie dense and so should be used cautiously.”

Do you personally avoid all added oils?

Dr. Davis: “I don’t avoid oils at all. I love olive oil. I don’t overdo oils, but I certainly don’t avoid them.”

Dr. Aggarwal is an adjunct Associate Professor in the University of Florida’s Division of Cardiovascular Medicine where she conducts research on the impact of nutrition in chronic illness. She is the co-author of Body on Fire: How Inflammation Triggers Chronic Illness and the Tools We Have to Fight It. Notably, Aggarwal co-authored the 2024 Recipe for Heart Health Trial, which studied the impacts of olive oil and whole-food plant-based diets in 40 adults at risk for cardiovascular disease.

How do you counsel patients on consuming olive oil and vegetable oils?

Dr. Aggarwal: “I tell my patients there's no negative in having a little bit of oil, especially if you're on the leaner side. But don't be under the misconception that oil is good for your health. I tell people to focus on eating more fruits and vegetables, more beans and [whole plant foods] because we know for sure that when you eat those foods, the fiber, the low saturated fat, you're going to do better.

“I think there's more data needed in the olive oil debate. But at this point, my feeling is we don't need olive oil or other oils for our health, but certainly there's no significant harm in eating a little bit of oil in your diet.”

Do you personally avoid all added oils?

Dr. Aggarwal: “I eat a little bit of oil in my personal diet. … I eat very clean and I have a very good LDL and I have a normal body mass, so keep that in mind; that's important. When I go out for a meal … I don't restrict the oil. When I cook at home, which I primarily do, sometimes I will use maybe less than a tablespoon of oil to cook 2 pounds of lentils. So very, very little oil in general. But I'm not afraid of a little bit of oil in my diet or my family's diet.”

Dr. Greger is a physician specializing in clinical nutrition, a founding member and Fellow of the American College of Lifestyle Medicine, and founder of the nonprofit NutritionFacts.org. He is the author of the New York Times bestsellers How Not to Die, The How Not to Die Cookbook, How Not to Diet, and How Not to Age.

How do you counsel patients on consuming olive oil and vegetable oils?

Dr. Greger: “The healthiest sources of fat are whole plant foods like nuts, seeds, and avocados. If people are going to use oil, I would recommend extra-virgin olive oil, which is better than refined vegetable oils, and refined oils are better than tropical oils and animal fats.”

Brenda Davis is a registered dietitian, speaker, and consultant specializing in plant-based nutrition. She has authored/co-authored 12 books, including Plant-Powered Protein and Nourish: The Definitive Plant-based Nutrition Guide for Families.

How do you counsel patients on consuming olive oil and vegetable oils?

Brenda Davis: “It depends on the individual. For those who are struggling with overweight or obesity, or chronic diseases such as Type 2 diabetes or cardiovascular disease, it makes sense to minimize or avoid oils as they are calorie-dense but nutrient-poor compared to whole foods like nuts, seeds, and avocados. To optimize the diet for effective treatment, it is best to prioritize whole plant foods over oils. On the other hand, oils can have a place in a healthy diet, as evidenced by many populations who include oils in their traditional diets, including all of the Blue Zones.

“For active individuals or those with high caloric requirements, good-quality oils can help meet energy needs without increasing the bulkiness of the diet. Also, oils have value from a culinary and cultural perspective, enhancing the flavor, texture, and enjoyment of foods.

“Of course, the health effects of oils depend on what they replace in the diet. If oils replace animal fats (e.g., butter, lard), they are beneficial. Switching from saturated fats to unsaturated vegetable oils reduces cardiovascular risk and overall mortality. However, if oils replace healthier whole plant foods, less favorable outcomes would be expected. Whole plant fats contain protective factors such as fiber, antioxidants, and phytonutrients that extracted oils lack. Oils are energy-dense and lack fiber, making them more prone to passive overconsumption of calories.

“The bottom line is that vegetable oils can be part of a healthful diet when used appropriately, but fats from whole foods remain the superior choice for long-term health.”

Do you personally avoid all added oils?

Brenda Davis: “I minimize my use of oils but do not completely avoid them. For example, I like to include a little sesame oil for flavor in a peanut sauce. I sometimes add a little oil to homemade cheeses for special occasions. I do not worry about oil avoidance when eating out (although I rarely eat out).

“The reason I am not rigid about oil avoidance is that I view oil in much the same way that I view sugar. These foods are not poisons, but they are generally best minimized. We want most of our macronutrients to be intrinsic to fiber-rich plant foods. Of course, the health impacts of oils and sugars depend on their source and quality. Organic blackstrap molasses has more value than white sugar, just as fresh-pressed flaxseed oil has more value than highly refined soybean oil.

“Unlike refined sugars, which have little redeeming value, high-quality oils typically supply essential fatty acids, vitamin E, and vitamin K, along with beneficial phytonutrients such as polyphenols in extra virgin olive oil. They also boost the absorption of valuable fat-soluble nutrients.

“My goals extend beyond human health to ethical and ecological issues. I want to see a mainstream shift toward healthy plant-based diets. I believe we will have greater success in achieving these goals if the diet is inclusive, honors cultural traditions, and allows some flexibility. We need to empower people to make healthy, plant-forward choices without creating barriers that may discourage consumers from embracing this compassionate, sustainable, healthful way of life.”

Dr. Katz is a specialist in preventive and lifestyle medicine, with particular expertise in nutrition. He is the president and founder of True Health Initiative, founder and CEO of Diet ID, Inc., and a past president of The American College of Lifestyle Medicine.

How do you counsel patients on consuming olive oil and vegetable oils?

Dr. Katz: “Optimal diet is as optimal diet does. Per Gertrude Stein: a difference, to be a difference, must make a difference. In other words, it is outcomes—for our own health, the well-being of our fellow creatures, the sustainable health of the planet—that matter most, and in turn define the healthfulness of diet. Through these several lenses, optimal diet is a theme, not one dogmatic prescription. Bountiful evidence associates optimal outcomes with whole-food, plant-predominant (or plant-exclusive) diets with or without the inclusion of select, extracted oils—most notably, extra-virgin olive oil. My counseling accordingly makes this a choice.”

Do you personally avoid added oils?

Dr. Katz: “No. My wife was raised in southern France, and there is a strong Mediterranean influence on her cooking and our eating. High-quality EVOO is a staple in the Katz kitchen, as are several other oils (most notably, organic expeller-pressed canola) because of their uses in cuisine, their enhancement of culinary pleasure, and their compatibility with optimal health outcomes, as noted above. To be clear, we have no randomized controlled trials directly comparing optimized plant-based diets of standardized overall quality, differing only by the inclusion or exclusion of select, extracted oils. I would be very interested in such a study! Until or unless it is conducted, the evidence we have suggests parity.”

Drs. Pulde and Lederman are practicing physicians specializing in nutrition and lifestyle medicine and the co-founders of WeHeal. They created the medical program used in the Forks Over Knives film and in the Whole Foods Market Medical & Wellness Centers, and co-authored the New York Times bestselling The Forks Over Knives Plan and The Whole Foods Diet.

How do you counsel patients on consuming olive oil and vegetable oils?

Drs. Pulde and Lederman: “Our goal is to provide evidence-based guidance to help patients make informed choices about their health. When discussing oil, we share the following key points:

“For these reasons, we advise minimizing or eliminating oil from the diet.”

Do you personally avoid added oils?

Drs. Pulde and Lederman: “We believe there is nothing beneficial that oil provides to a diet. We may consume oil on occasion, such as when dining out, traveling, or at social events where options are limited. However, whenever possible and always at home, we choose to avoid all oils, even in small amounts.”

Dr. Kahn is an integrative cardiologist; the founder of the Kahn Center for Cardiac Longevity in Bingham Farms, Michigan; and the author of several books, including The Plant-Based Solution: America's Healthy Heart Doc's Plan to Power Your Health.

How do you counsel patients on consuming olive oil and vegetable oils?

Dr. Kahn: “I am ‘oil flexible’ with my cardiac patients. If they have advanced heart disease, weight issues, diabetes issues, or prefer to follow a no-SOS [no added salt, oil, or sugar] diet, I am completely supportive. I followed the same diet for decades and my wife still cooks that way at home. If they are not in the groups I mentioned, I recommend certain brands of organic, ice-pressed extra-virgin olive oil at a dose of about 1 to 2 tablespoons a day or less. I am unable to ignore the impressive data from the CORDIOPREV randomized trial that followed 1,002 heart patients in Spain for seven years and found impressive advantages to the higher olive oil group. I do not find the current craze labelling all seed oils as toxic to be authentic with the science but I do not use or advise them unless patients have a strong personal preference.”

Do you personally avoid added oils?

Dr. Kahn: “I am back and forth on oils in my own diet. I did decades oil-free. I owned restaurants that offered oil-free menus, unique in the food industry overall. In the last five years I have added back high-quality EVOO, but 1 tablespoon at most a day. Recently I have returned to a no-oil diet at home but it may swing back again. I do not think eating should cause profound anxiety, and I see many patients extremely tense about this topic to a point where it causes them harm and loss of joy while dining.”